RESEARCH Researchers from The Cleveland Clinic (Ohio) had 32 male and female subjects perform a static hamstring stretch (reach and hold) every day for four weeks. After the four-week trial, subjects were divided into two groups. The first stopped stretching for the four remaining weeks of the study. The second group stretched two or three times per week for another four weeks.
FINDINGS Both groups increased their hamstring flexibility by about 20 degrees during the first four weeks. Those who did not stretch during weeks five through eight lost seven degrees of flexibility, but those who stretched just two or three days per week gained an additional four degrees of flexibility.
CONCLUSION The more days you stretch the better, but you can make decent gains in your flexibility by stretching just two or three days per week.
APPLICATION Make sure to perform static stretching after your workouts and never before. Doing static stretches before workouts will decrease muscle strength and limit increases in flexibility. Stretching after workouts further increases flexibility without compromising strength.